1. Field of the Invention
This invention relates to a build-up spraying apparatus, and more particularly to a build-up spraying apparatus particularly suitable for use in the repairing of local or partial wear of a metal article such as a rail by build-up spraying of metal powder.
2. Description of the Prior Art
Recently, a need has highly existed for techniques of efficiently repairing the local or partial wear of a rail without exchanging the rail. In order to meet such demand, it has been proposed to deposit metal powder on such wear portion of a rail by build-up spraying.
A conventional build-up spraying apparatus which has been used for such purpose includes a build-up spraying burner which is adapted to uniformly spread build-up metal powder together with carrier gas thereon toward an article to be subjected to build-up spraying and heat and melt the metal powder by flame ejected from the burner on the way to the article, to thereby uniformly deposit the molten metal powder on the surface of the article. The build-up portion of the article is subsequently ground by means of a grinder or the like to be flush with the remaining portion thereof.
As can be seen from the foregoing, the conventional build-up spraying burner is adapted to form build-up of a uniform thickness in the spreading direction of build-up metal powder perpendicular to the traveling direction of the apparatus. However, the burner cannot form build-up sufficient to repair wear different in depth with location such as the local wear or partial wear of a rail, because it carries out build-up spraying regardless of such local or partial wear. Thus, the repairing operation using the conventional build-up spraying apparatus is much troublesome, because an operation is indispensable which renders the built-up portion flush with the remaining portion after forming build-up.